Magazines for portable firearms are generally made up of an ammunition chamber, an elevating mechanism which supports the ammunition in the chamber, and a spring that generally pushes upwards the elevating mechanism and the ammunition for chambering when the firearm is operated.
The top part of the chamber usually has two rigid facing lips that are slightly bent inwards to intercept and hold the ammunition in the chamber at one end and in opposition to the thrust of the spring on the elevating mechanism, while allowing it to be sent to the cartridge chamber of the gun.
In conventional magazines it is quite difficult to load ammunition into the chamber if done by hand, as generally occurs, or without the aid of specially designed devices. Loading takes place in two stages and with combined movements.
First it is necessary to position the ammunition and exercise with it a pressure on the front part not engaged by the chamber lips, at the top of the column of cartridges already loaded, so as to find enough space to house the new ammunition below the lips. PA1 Then, while maintaining sufficient pressure to counteract the thrust of the spring on the elevating mechanism, the ammunition must be pushed in lengthwise on top of the one below until it comes up against the back wall of the chamber and positioned underneath the lips.